[Tarboy56]

This may be long and somewhat confusing so bare with me. I have a stock 56 Belair 265 cu.in V-8 two barrel carb powerglide. The problem is upon acceleration it falls flat on its face like it is out of fuel. This is what I have done thus far.
New carb (actually have tried three carbs) no change in condition
new points, plugs, condenser no change
new coil and resistor no change
totally by passed gas tank and fuel pump with secondary systen no change
cleaned and freeded up the exhaust manifold heat riser no change
tried two new distributors no change
reset carb float level no chage
timing is slightly advanced played with it no change
Car starts right up idels smooth and takes acceleration fine with no load runs fairly well once you get over 20MPH completely cuts out from a dead stop or if you try to take off quick it simply stalls and dies. I have NO idea of what to do moving forward any ideas?

[hcompton]

Originally Posted by Tarboy56

This may be long and somewhat confusing so bare with me. I have a stock 56 Belair 265 cu.in V-8 two barrel carb powerglide. The problem is upon acceleration it falls flat on its face like it is out of fuel. This is what I have done thus far.
New carb (actually have tried three carbs) no change in condition
new points, plugs, condenser no change
new coil and resistor no change
totally by passed gas tank and fuel pump with secondary systen no change
cleaned and freeded up the exhaust manifold heat riser no change
tried two new distributors no change
reset carb float level no chage
timing is slightly advanced played with it no change
Car starts right up idels smooth and takes acceleration fine with no load runs fairly well once you get over 20MPH completely cuts out from a dead stop or if you try to take off quick it simply stalls and dies. I have NO idea of what to do moving forward any ideas?

Do you have a volt meter hooked up. Does the voltage drop when the problem happens. How about the battery is it strong. Maybe low on water and dropping out. Engine ground hooked up? Coil burned up shorting to ground under a load. Also have you changed out the wires and checked the power wires to the coil and points.

I take it you tried good fresh gas? Any small fuel lines that might be blocked. Maybe something close to the carb that keeps getting switched over.

Sounds like you tried just about everything. Could it be knocking and falling down.

[Tarboy56]

hcomptom,
new battery wireing all new new coil we did check dwel and voltage all were fine it acts exactly like a fulty accelator pump but I have tried many new and other carbs no luck. In the chevy manual they discuss the heat riser i assume it it supposed to be closed when engine is cold to direct heat to the intake & carb then after warmed up it opens to allow exhauust to flow out the exhaust hav you ever had issues with this?

[vinniekq2]

hcompton
exactly what he says,check voltage and generator out put.Is there a resister on the points?try driving slowly and putting the lights on

[Tarboy56]

The generator is also brand new and voltage reuglator when installes and polorized voltage was right on. I will do some voltage checks and check the ground also. Any other thoughts ? Would you know of anyone who is an expert on these engines I could call?

[vinniekq2]

The most knowledgeable 56 chevy,265 guy I know of is Richard Johnson,Richmond BC.No idea how to contact him.

[dwwl]

I maybe wrong, but check for a vacuum leak, Father in law had the problem many many years ago on 55 chevy. Just drove him crazy. was going to sell the car and a old guy sprayed the base of the carb with staring fluid and it stubbled. Gasket on bottum of carb was leaking. Give that a try.

[Frankinforesthill]

You said you tried different carbs,,,, But did you check to see if the accerletor pump is pumping???

[Tarboy56]

I did spray some wd-40 around the base of the carb. as well as the intake I didn't see any visible signs of a leak the accelerator pump squirts two strong squirts of fuel when I hit the throttle when not under a load. I even put a carb. off a running car on and it made NO difference. I'm pretty good at this stuff and my BRO is a professional engine builder this has us both stumped !!!!

[dwwl]

When you ever get it solved let the rest of us know what you found, i'm always interested in knowing what stumps me.

[Tarboy56]

Will do IF I ever get it figured out

[seltec8]

Check if the vacum and mechanical advance work freely and if the ground strap is good and flexible to the distributor plate.

[Tarboy56]

I will give this a good close look

[cdminter59]

How old is the exhaust system. Could the exhaust pipe or muffler colapsed from the inside? I seen this before. Runs fine until you try to getup to speed.

[Tarboy56]

Good question everything is pretty new very few miles on the car since it was restored.